Continuous data protection enables a user to be able to access or restore a previous state with finer time granularity than previously offered by some traditional backup solutions. For example, some traditional backup solutions perform backups at discrete points in time that are separated by hours or even days. The only previous states that a user is able to restore are the states corresponding to those points in time. With continuous data protection, data (e.g., a file or other data associated with a continuously protected device) is continuously protected over a window of time and a user is able to access any prior state within that window. For example, using some continuous data protection systems a user can access or restore saved states that are single writes apart.
To continuously protect data, previous version data is obtained and stored. Typically, storage used to store previous version data is reclaimed as the data stored in particular locations is no longer required to be retained, e.g., because it relates to states that fall outside (i.e., prior to the earliest/beginning edge of) a rolling window. However, reclaiming and reusing storage as the need to retain the data stored therein ends may in some cases lead to inefficient recovery and/or reallocation of storage. Therefore, there is a need for a way to efficiently reclaim and reuse storage used to store previous version data.